Oil or fat, as one of the three main nutrients, is an essential part of the daily diet. Oxidation of oil and fat is an important factor affecting the quality of oils. The automatic oxidation of oil and fat is a spontaneous oxidation reaction of activated olefin-containing substrates (such as unsaturated oils) and oxygen in the air at room temperature without any direct illumination or any catalyst. The products produced by oxidation have an adverse effect on the flavor, color and texture of the edible oil and fat, resulting in shortening the shelf life and reducing the nutritional quality of the oil and fat. Oxidation of oil and fat can cause damage to membranes, enzymes and proteins, leading to many diseases of aging and even carcinogenicity, which harms human health. Therefore, prevention of oxidation of oil and fat in foods and fats is a major concern for human health, and the most common way to prevent oxidation of oils is to add antioxidants.
Hydroxytyrosol (4-(2-hydroxyethyl)-1,2-benzenediol; compound of formula (II)) is a phenylethanoid, a type of phenolic phytochemical with antioxidant properties in vitro. In nature, hydroxytyrosol is found in olive leaf and olive oil, in the form of its elenolic acid ester oleuropein and, especially after degradation, in its plain form.

P-Phenylene diisocyanate (1,4-phenylene diisocyanate, PPDI) is a symmetrical aromatic diisocyanate. It reacts with a chain extender to synthesize a polyurethane elastomer with high cohesive energy and good heat resistance. The polyurethane PUE elastomer has good hardness, temperature resistance and dynamic performance, wear resistance, toughness, solvent resistance and heat and humidity resistance, and is a promising high-performance material.

In the present invention, p-phenylene diisocyanate is modified by the hydroxytyrosol structure to obtain hydroxytyrosol p-phenylenedicarboxylate while eliminating the toxic group of p-phenylene diisocyanate. Hydroxytyrosol p-phenylenedicarboxylate has excellent antioxidant activity and high medical research and application value in the field of antioxidant products.